Commit e4788edc authored by Kees Cook's avatar Kees Cook Committed by Greg Kroah-Hartman
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USB: EHCI: Add alias for Broadcom INSNREG 



Refactor struct ehci_regs to avoid accessing beyond the end of
port_status. This change results in no difference in the final
object code.

Avoids several warnings when building with -Warray-bounds:

drivers/usb/host/ehci-brcm.c: In function 'ehci_brcm_reset':
drivers/usb/host/ehci-brcm.c:113:32: warning: array subscript 16 is above array bounds of 'u32[15]' {aka 'unsigned int[15]'} [-Warray-bounds]
  113 |  ehci_writel(ehci, 0x00800040, &ehci->regs->port_status[0x10]);
      |                                ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
In file included from drivers/usb/host/ehci.h:274,
                 from drivers/usb/host/ehci-brcm.c:15:
./include/linux/usb/ehci_def.h:132:7: note: while referencing 'port_status'
  132 |   u32 port_status[HCS_N_PORTS_MAX];
      |       ^~~~~~~~~~~

Note that the documentation around this proprietary register was
confusing. If "USB_EHCI_INSNREG00" is at port_status[0x0f], its offset
would be 0x80 (not 0x90). The comments have been adjusted to fix this
apparent typo.

Fixes: 9df23151 ("usb: ehci: Add new EHCI driver for Broadcom STB SoC's")
Cc: Al Cooper <alcooperx@gmail.com>
Cc: Alan Stern <stern@rowland.harvard.edu>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: linux-usb@vger.kernel.org
Cc: bcm-kernel-feedback-list@broadcom.com
Suggested-by: default avatarArnd Bergmann <arnd@arndb.de>
Acked-by: default avatarAlan Stern <stern@rowland.harvard.edu>
Signed-off-by: default avatarKees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20210818173018.2259231-3-keescook@chromium.org


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 72dd1843

drivers/usb/host/ehci-brcm.c

+4 −7
Original line number Diff line number Diff line
@@ -108,10 +108,9 @@ static int ehci_brcm_reset(struct usb_hcd *hcd) 
	/*

	 * SWLINUX-1705: Avoid OUT packet underflows during high memory

	 *   bus usage

	 * port_status[0x0f] = Broadcom-proprietary USB_EHCI_INSNREG00 @ 0x90

	 */

	ehci_writel(ehci, 0x00800040, &ehci->regs->port_status[0x10]);

	ehci_writel(ehci, 0x00000001, &ehci->regs->port_status[0x12]);

	ehci_writel(ehci, 0x00800040, &ehci->regs->brcm_insnreg[1]);

	ehci_writel(ehci, 0x00000001, &ehci->regs->brcm_insnreg[3]);



	return ehci_setup(hcd);

}
@@ -223,11 +222,9 @@ static int __maybe_unused ehci_brcm_resume(struct device *dev) 
	/*

	 * SWLINUX-1705: Avoid OUT packet underflows during high memory

	 *   bus usage

	 * port_status[0x0f] = Broadcom-proprietary USB_EHCI_INSNREG00

	 * @ 0x90

	 */

	ehci_writel(ehci, 0x00800040, &ehci->regs->port_status[0x10]);

	ehci_writel(ehci, 0x00000001, &ehci->regs->port_status[0x12]);

	ehci_writel(ehci, 0x00800040, &ehci->regs->brcm_insnreg[1]);

	ehci_writel(ehci, 0x00000001, &ehci->regs->brcm_insnreg[3]);



	ehci_resume(hcd, false);

include/linux/usb/ehci_def.h

+10 −3
Original line number Diff line number Diff line
@@ -176,16 +176,23 @@ struct ehci_regs { 
#define USBMODE_CM_HC	(3<<0)		/* host controller mode */

#define USBMODE_CM_IDLE	(0<<0)		/* idle state */

	};

	u32		reserved4;



/* Moorestown has some non-standard registers, partially due to the fact that

 * its EHCI controller has both TT and LPM support. HOSTPCx are extensions to

 * PORTSCx

 */

	union {

		struct {

			u32	reserved4;

			/* HOSTPC: offset 0x84 */

			u32	hostpc[HCS_N_PORTS_MAX];

#define HOSTPC_PHCD	(1<<22)		/* Phy clock disable */

#define HOSTPC_PSPD	(3<<25)		/* Port speed detection */

		};



		/* Broadcom-proprietary USB_EHCI_INSNREG00 @ 0x80 */

		u32	brcm_insnreg[4];

	};



	u32		reserved5[2];